The infection of green tissue, flower clusters and buds by spores results in fungal diseases common to the grape family and most agricultural crops. When spore infection occurs, conidia are produced and the disease spreads rapidly throughout the plant. The spread of disease is enhanced if the combination of temperature, leaf wetness and time are satisfied. Some of the fungal diseases that attack plants, such as grapes and strawberries in particular, are: (1) powdery mildew, (2) Downey mildew, (3) black rot, (4) Phomopsis Cane and Leaf Spot, (5) Eutypa Dieback.
To combat mildew, such as powdery mildew, a common approach is to apply liberal doses of fungicides by broad coverage spraying techniques using spray applicators. The use of chemical sprayers can produce potential side effects and/or be harmful to plants. The use of pesticides is compounded with problems for plant growers due to their chemical nature, the necessary safety precautions required, government regulations, and some consumers' reluctance to eat produce treated with pesticides. The spray operator, for his/her own safety, is required to wear protective clothing, a special breathing mask, eye goggles, and water proof gloves to prevent contamination by toxic pesticides.
Present fungicides work by being absorbed within the plant tissue (the fungicide is systemic) or providing a protective coating on the surface. The fungicide can act as a protectant to prevent infection, or if the plant is already infected, the fungicide can act as an eradicant to stop infection or as an antisporulant to prevent disease spread.
Ultraviolet radiation can be effective for combating various types of mildew. However, currently available mildew equipment generally employs ultraviolet mercury lamps radiating at a peak wavelength of 254 nanometers.